India is currently seeing a surge in viral infections, led primarily by the spread of swine flu, H3N2, and COVID-19 viruses. Experts believe that at least five different types of respiratory viruses are causing widespread illness, ranging from mild to extreme severity, over the past couple of months.

According to the Integrated Disease Surveillance Programme (IDSP), there is an upswing seen in influenza-like illness (ILI) or severe acute respiratory infection (SARI) across the country. Additionally, since January 1, 2023, as per testing of respiratory samples being undertaken by various viral research and diagnostic labs, almost 25.4 per cent of the samples have tested positive for adenoviruses.

Real-time surveillance by the IDSP shows that 955 cases of H1N1, also referred to as swine flu, have been reported by states in 2023 till February 28. Data also shows that apart from swine flu, the COVID-19 virus, the influenza A subtype H3N2 virus, and the seasonal Victoria and Yamagata lineage of influenza B viruses are in circulation. The H3N2 virus is the dominant virus in India as of now even as cases of swine flu (H1N1) are also gradually increasing in several parts of the country.

According to the latest data available on the IDSP’s Integrated Health Information Platform (IDSP-IHIP), a total of 3038 laboratory-confirmed cases of various subtypes of Influenza including H1N1 and H3N2 have been reported till 9th March 2023 by the States. This includes 1245 cases in January, 1307 in February and 486 cases in March (till 9th March). This surge is led predominantly by H3N2. At least three deaths have been reported due to H3N2, one each in Gujarat, Haryana and Karnataka.

At least 9 people died due to seasonal influenza A (H1N1) in India in January alone, as per the data released by the National Centre for Disease Control (NCDC). These have have been reported from Haryana (2), Kerala (2), Maharashtra (2), Punjab (2) and Tamil Nadu (1) in January with a total of 451 cases excluding data from West Bengal. As of February 28, a majority of H1N1 cases are reported from Tamil Nadu (545), Maharashtra (170), Gujarat (170), Kerala (42) and Punjab (28), the health ministry said in a recent statement.

Further, the IDSP-IHIP data from health facilities indicate that during the month of January 2023, a total of 397,814 cases of Acute Respiratory Illness/Influenza Like Illness (ARI/ILI) were reported from the country which increased slightly to 436,523 during February 2023. In the first 9 days of March 2023, this number stands at 133,412 cases.

Symptoms, prevention and treatment

Seasonal influenza is an acute respiratory infection caused by influenza viruses circulating in different regions across the globe, and as the name suggests, infections peak during specific months. India witnesses two seasonal influenza peaks yearly.

While most of these agents typically cause a similar, mild and often self-limiting illness manifesting into respiratory infection with fever and cough, in some cases, particularly old age people, people with obesity, and other co-morbidities as well as pregnant females, those infected may suffer from a more severe manifestation of these diseases requiring hospitalisation.

Symptoms of H3N2 influenza are similar to that of any other flu. They include cough, fever, body ache and headache, sore throat, a runny or stuffy nose, extreme fatigue and breathlessness in severe cases. However, this year’s surge led by Influenza subtype A H3N2 seems to be impacting people with more severity than usual, leading to hospitalisation and even death. H3N2 is known to cause more severe illness in young children and older adults.

Generally, viral illnesses are treated symptomatically based on the patient’s clinical condition. However, annual seasonal influenza vaccines, also known as quadrivalent vaccines, are available against the H3N2 subtype.

Experts across the board have reiterated the importance of practising COVID-appropriate behaviour in limiting influenza’s spread, such as wearing masks, maintaining hand hygiene and safe distancing. In India, low vaccination rates combined with heavy air pollution worsen the effects of the flu.

Steps taken by the Governments

Perturbed over the rising respiratory illnesses in the country, the union health ministry recently wrote to all states mentioning that while Influenza is an annual seasonal occurrence, in the present season, a variety of weather conditions and behavioural reasons (like less than adequate attention to personal hygiene, sneezing and coughing without adequate protection in close proximity of other people, closed indoor gatherings of people, etc.) make the environment conducive to the circulation of a number of viral respiratory pathogens like Influenza A (HIN1, H3N2 etc.) and adenoviruses, etc.

The union government also reiterated that while the Covid-19 trajectory has decreased substantially in the last few months, the gradual rise in Covid-19 test positivity rates in some states is a concerning issue that needs to be promptly addressed.

In light of these developments, the Ministry is keeping a close watch on the seasonal influenza situation in various states and union territories through the IDSP network on a real-time basis. The Centre in its letter to the states and UTs states, “under integrated disease surveillance programme, as reported by states an increasing trend of ILI and SARI is being observed across the country. As per integrated sentinel-based surveillance of ILI and SARU, an upswing of Influenza A is observed since the latter half December 2022.”

In the national capital, Delhi, hospitals are witnessing increased ICU admissions with H3N2 viral pneumonia, mostly with severe co-morbidities and older than 75. Several states across the country have sprung into action to contain the spread of H3N2 infection. As per the latest reports from Puducherry, the state government has declared a holiday for all schools from March 16 to March 26 in the wake of the H3N2 spread. In addition to H3N2 and COVID-19, the Tamil Nadu health department is also dealing with a spike in H1N1 virus or swine flu cases. Meanwhile, in the neighbouring state of Kerala, the total caseload has risen to 13, with maximum reports emerging from Palakkad, Alappuzha and Ernakulam.

Karnataka reported 26 H3N2 cases last week, and Andhra Pradesh recorded 74 hospital admissions in the previous two months. The numbers are also surging in Maharashtra, which recorded 352 cases so far, while Gujarat has reported three cases of H3N2, excluding a suspected death due to influenza-like illness.

Further, following the emergence of 59 cases, Odisha has also intensified its ILI (influenza-like illness) and SARI (severe acute respiratory infections) surveillance system. At the same time, hospitals in Uttar Pradesh and Bihar have ramped up preparations in the likely event of a surge.

The Central government has requested all states and Union territories to follow operational guidelines for integrated surveillance of respiratory pathogens presenting as cases of ILI or SARI. The states were also requested to take a stock of hospital preparedness such as the availability of drugs and medical oxygen, and vaccination coverage against COVID-19 and influenza.

Before H3N2 became dominant on January 1 this year, swine flu was the leading cause of respiratory infections between April 18, 2022, and December 31, 2022. H3N2 was, however, present all through the year 2022, but lying low with fewer infections. Covid-19 was dominant from December 27, 2021, to February 27, 2022, peaking in mid-January 2022.







Photo Credits: Business Today

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